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2008-11-28Merge branch 'master' of ↵David S. Miller
git://git.kernel.org/pub/scm/linux/kernel/git/kaber/nf-next-2.6 Conflicts: net/netfilter/nf_conntrack_netlink.c
2008-11-25net: Use a percpu_counter for sockets_allocatedEric Dumazet
Instead of using one atomic_t per protocol, use a percpu_counter for "sockets_allocated", to reduce cache line contention on heavy duty network servers. Note : We revert commit (248969ae31e1b3276fc4399d67ce29a5d81e6fd9 net: af_unix can make unix_nr_socks visbile in /proc), since it is not anymore used after sock_prot_inuse_add() addition Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25netns xfrm: per-netns MIBsAlexey Dobriyan
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25netns xfrm: AH/ESP in netns!Alexey Dobriyan
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25netns xfrm: ->get_saddr in netnsAlexey Dobriyan
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25netns xfrm: ->dst_lookup in netnsAlexey Dobriyan
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25netns xfrm: KM reporting in netnsAlexey Dobriyan
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25netns xfrm: dst garbage-collecting in netnsAlexey Dobriyan
Pass netns pointer to struct xfrm_policy_afinfo::garbage_collect() [This needs more thoughts on what to do with dst_ops] [Currently stub to init_net] Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25netns xfrm: lookup in netnsAlexey Dobriyan
Pass netns to xfrm_lookup()/__xfrm_lookup(). For that pass netns to flow_cache_lookup() and resolver callback. Take it from socket or netdevice. Stub DECnet to init_net. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25netns xfrm: state lookup in netnsAlexey Dobriyan
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25netns xfrm: add struct xfrm_state::xs_netAlexey Dobriyan
To avoid unnecessary complications with passing netns around. * set once, very early after allocating * once set, never changes For a while create every xfrm_state in init_net. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25ipv6: fix warning in net/ipv6/ip6_flowlabel.cIngo Molnar
this warning: net/ipv6/ip6_flowlabel.c: In function ‘ipv6_flowlabel_opt’: net/ipv6/ip6_flowlabel.c:467: warning: ‘err’ may be used uninitialized in this function triggers because GCC does not recognize the (correct) error flow between fl_create() and 'err'. Annotate it. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25netfilter: nfmark IPV6 routing in OUTPUT, mangle, NFQUEUEEric Leblond
This patch let nfmark to be evaluated for routing decision for OUTPUT packet, in mangle table, when process paquet in NFQUEUE. This patch is an IPv6 port of Laurent Licour IPv4 one. Signed-off-by: Eric Leblond <eric@inl.fr> Signed-off-by: Patrick McHardy <kaber@trash.net>
2008-11-25xfrm: remove useless forward declarationsAlexey Dobriyan
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-25ah4/ah6: remove useless NULL assignmentsAlexey Dobriyan
struct will be kfreed in a moment, so... Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-23net: fix tunnels in netns after ndo_ changesAlexey Dobriyan
dev_net_set() should be the very first thing after alloc_netdev(). "ndo_" changes turned simple assignment (which is OK to do before netns assignment) into quite non-trivial operation (which is not OK, init_net was used). This leads to incomplete initialisation of tunnel device in netns. BUG: unable to handle kernel NULL pointer dereference at 00000004 IP: [<c02efdb5>] ip6_tnl_exit_net+0x37/0x4f *pde = 00000000 Oops: 0000 [#1] PREEMPT DEBUG_PAGEALLOC last sysfs file: /sys/class/net/lo/operstate Pid: 10, comm: netns Not tainted (2.6.28-rc6 #1) EIP: 0060:[<c02efdb5>] EFLAGS: 00010246 CPU: 0 EIP is at ip6_tnl_exit_net+0x37/0x4f EAX: 00000000 EBX: 00000020 ECX: 00000000 EDX: 00000003 ESI: c5caef30 EDI: c782bbe8 EBP: c7909f50 ESP: c7909f48 DS: 007b ES: 007b FS: 0000 GS: 0000 SS: 0068 Process netns (pid: 10, ti=c7908000 task=c7905780 task.ti=c7908000) Stack: c03e75e0 c7390bc8 c7909f60 c0245448 c7390bd8 c7390bf0 c7909fa8 c012577a 00000000 00000002 00000000 c0125736 c782bbe8 c7909f90 c0308fe3 c782bc04 c7390bd4 c0245406 c084b718 c04f0770 c03ad785 c782bbe8 c782bc04 c782bc0c Call Trace: [<c0245448>] ? cleanup_net+0x42/0x82 [<c012577a>] ? run_workqueue+0xd6/0x1ae [<c0125736>] ? run_workqueue+0x92/0x1ae [<c0308fe3>] ? schedule+0x275/0x285 [<c0245406>] ? cleanup_net+0x0/0x82 [<c0125ae1>] ? worker_thread+0x81/0x8d [<c0128344>] ? autoremove_wake_function+0x0/0x33 [<c0125a60>] ? worker_thread+0x0/0x8d [<c012815c>] ? kthread+0x39/0x5e [<c0128123>] ? kthread+0x0/0x5e [<c0103b9f>] ? kernel_thread_helper+0x7/0x10 Code: db e8 05 ff ff ff 89 c6 e8 dc 04 f6 ff eb 08 8b 40 04 e8 38 89 f5 ff 8b 44 9e 04 85 c0 75 f0 43 83 fb 20 75 f2 8b 86 84 00 00 00 <8b> 40 04 e8 1c 89 f5 ff e8 98 04 f6 ff 89 f0 e8 f8 63 e6 ff 5b EIP: [<c02efdb5>] ip6_tnl_exit_net+0x37/0x4f SS:ESP 0068:c7909f48 ---[ end trace 6c2f2328fccd3e0c ]--- Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-23net: Convert TCP/DCCP listening hash tables to use RCUEric Dumazet
This is the last step to be able to perform full RCU lookups in __inet_lookup() : After established/timewait tables, we add RCU lookups to listening hash table. The only trick here is that a socket of a given type (TCP ipv4, TCP ipv6, ...) can now flight between two different tables (established and listening) during a RCU grace period, so we must use different 'nulls' end-of-chain values for two tables. We define a large value : #define LISTENING_NULLS_BASE (1U << 29) So that slots in listening table are guaranteed to have different end-of-chain values than slots in established table. A reader can still detect it finished its lookup in the right chain. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-21net: remove redundant argument commentsQinghuang Feng
Remove redundant argument comments in files of net/* Signed-off-by: Qinghuang Feng <qhfeng.kernel@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-20net: convert TCP/DCCP ehash rwlocks to spinlocksEric Dumazet
Now TCP & DCCP use RCU lookups, we can convert ehash rwlocks to spinlocks. /proc/net/tcp and other seq_file 'readers' can safely be converted to 'writers'. This should speedup writers, since spin_lock()/spin_unlock() only use one atomic operation instead of two for write_lock()/write_unlock() Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-20ipv6: convert tunnels to net_device_opsStephen Hemminger
Like IPV4, convert the tunnel virtual devices to use net_device_ops. Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-20ipmr: convert ipmr virtual interface to net_device_opsStephen Hemminger
Convert to new network device ops interface. Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-20Merge branch 'master' of ↵David S. Miller
master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 Conflicts: drivers/net/ixgbe/ixgbe_main.c include/net/mac80211.h net/phonet/af_phonet.c
2008-11-20net: fix tiny output corruption of /proc/net/snmp6Alexey Dobriyan
Because "name" is static, it can be occasionally be filled with somewhat garbage if two processes read /proc/net/snmp6. Also, remove useless casts and "-1" -- snprintf() correctly terminates it's output. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-20ipv6: use seq_release_private for ip6mr.c /proc entriesBenjamin Thery
In ip6mr.c, /proc entries /proc/net/ip6_mr_cache and /proc/net/ip6_mr_vif are opened with seq_open_private(), thus seq_release_private() should be used to release them. Should fix a small memory leak. Signed-off-by: Benjamin Thery <benjamin.thery@bull.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-20netfilter: ip6table_filter: merge LOCAL_IN and FORWARD hooksAlexey Dobriyan
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Patrick McHardy <kaber@trash.net>
2008-11-20net: listening_hash get a spinlock per bucketEric Dumazet
This patch prepares RCU migration of listening_hash table for TCP/DCCP protocols. listening_hash table being small (32 slots per protocol), we add a spinlock for each slot, instead of a single rwlock for whole table. This should reduce hold time of readers, and writers concurrency. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-19ip: convert to net_device_ops for ioctlStephen Hemminger
Convert to net_device_ops function table pointer for ioctl. Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-19include/net net/ - csum_partial - remove unnecessary castsJoe Perches
The first argument to csum_partial is const void * casts to char/u8 * are not necessary Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-18Merge branch 'master' of ↵David S. Miller
master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 Conflicts: drivers/isdn/i4l/isdn_net.c fs/cifs/connect.c
2008-11-16net: Convert TCP & DCCP hash tables to use RCU / hlist_nullsEric Dumazet
RCU was added to UDP lookups, using a fast infrastructure : - sockets kmem_cache use SLAB_DESTROY_BY_RCU and dont pay the price of call_rcu() at freeing time. - hlist_nulls permits to use few memory barriers. This patch uses same infrastructure for TCP/DCCP established and timewait sockets. Thanks to SLAB_DESTROY_BY_RCU, no slowdown for applications using short lived TCP connections. A followup patch, converting rwlocks to spinlocks will even speedup this case. __inet_lookup_established() is pretty fast now we dont have to dirty a contended cache line (read_lock/read_unlock) Only established and timewait hashtable are converted to RCU (bind table and listen table are still using traditional locking) Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-16udp: Use hlist_nulls in UDP RCU codeEric Dumazet
This is a straightforward patch, using hlist_nulls infrastructure. RCUification already done on UDP two weeks ago. Using hlist_nulls permits us to avoid some memory barriers, both at lookup time and delete time. Patch is large because it adds new macros to include/net/sock.h. These macros will be used by TCP & DCCP in next patch. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-12ipv6: routing header fixesBrian Haley
This patch fixes two bugs: 1. setsockopt() of anything but a Type 2 routing header should return EINVAL instead of EPERM. Noticed by Shan Wei (shanwei@cn.fujitsu.com). 2. setsockopt()/sendmsg() of a Type 2 routing header with invalid length or segments should return EINVAL. These values are statically fixed in RFC 3775, unlike the variable Type 0 was. Signed-off-by: Brian Haley <brian.haley@hp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-11net: remove struct dst_entry::entry_sizeAlexey Dobriyan
Unused after kmem_cache_zalloc() conversion. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-11Merge branch 'master' of ↵David S. Miller
master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 Conflicts: drivers/message/fusion/mptlan.c drivers/net/sfc/ethtool.c net/mac80211/debugfs_sta.c
2008-11-10ipv6: fix ip6_mr_init error pathBenjamin Thery
The order of cleanup operations in the error/exit section of ip6_mr_init() is completely inversed. It should be the other way around. Also a del_timer() is missing in the error path. Signed-off-by: Benjamin Thery <benjamin.thery@bull.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-07Merge branch 'davem-next' of ↵David S. Miller
master.kernel.org:/pub/scm/linux/kernel/git/jgarzik/netdev-2.6
2008-11-06Merge branch 'master' of ↵David S. Miller
master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 Conflicts: drivers/net/wireless/ath5k/base.c net/8021q/vlan_core.c
2008-11-06bonding: send IPv6 neighbor advertisement on failoverBrian Haley
This patch adds better IPv6 failover support for bonding devices, especially when in active-backup mode and there are only IPv6 addresses configured, as reported by Alex Sidorenko. - Creates a new file, net/drivers/bonding/bond_ipv6.c, for the IPv6-specific routines. Both regular bonds and VLANs over bonds are supported. - Adds a new tunable, num_unsol_na, to limit the number of unsolicited IPv6 Neighbor Advertisements that are sent on a failover event. Default is 1. - Creates two new IPv6 neighbor discovery functions: ndisc_build_skb() ndisc_send_skb() These were required to support VLANs since we have to be able to add the VLAN id to the skb since ndisc_send_na() and friends shouldn't be asked to do this. These two routines are basically __ndisc_send() split into two pieces, in a slightly different order. - Updates Documentation/networking/bonding.txt and bumps the rev of bond support to 3.4.0. On failover, this new code will generate one packet: - An unsolicited IPv6 Neighbor Advertisement, which helps the switch learn that the address has moved to the new slave. Testing has shown that sending just the NA results in pretty good behavior when in active-back mode, I saw no lost ping packets for example. Signed-off-by: Brian Haley <brian.haley@hp.com> Signed-off-by: Jay Vosburgh <fubar@us.ibm.com> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2008-11-05ipv6: fix run pending DAD when interface becomes readyBenjamin Thery
With some net devices types, an IPv6 address configured while the interface was down can stay 'tentative' forever, even after the interface is set up. In some case, pending IPv6 DADs are not executed when the device becomes ready. I observed this while doing some tests with kvm. If I assign an IPv6 address to my interface eth0 (kvm driver rtl8139) when it is still down then the address is flagged tentative (IFA_F_TENTATIVE). Then, I set eth0 up, and to my surprise, the address stays 'tentative', no DAD is executed and the address can't be pinged. I also observed the same behaviour, without kvm, with virtual interfaces types macvlan and veth. Some easy steps to reproduce the issue with macvlan: 1. ip link add link eth0 type macvlan 2. ip -6 addr add 2003::ab32/64 dev macvlan0 3. ip addr show dev macvlan0 ... inet6 2003::ab32/64 scope global tentative ... 4. ip link set macvlan0 up 5. ip addr show dev macvlan0 ... inet6 2003::ab32/64 scope global tentative ... Address is still tentative I think there's a bug in net/ipv6/addrconf.c, addrconf_notify(): addrconf_dad_run() is not always run when the interface is flagged IF_READY. Currently it is only run when receiving NETDEV_CHANGE event. Looks like some (virtual) devices doesn't send this event when becoming up. For both NETDEV_UP and NETDEV_CHANGE events, when the interface becomes ready, run_pending should be set to 1. Patch below. 'run_pending = 1' could be moved below the if/else block but it makes the code less readable. Signed-off-by: Benjamin Thery <benjamin.thery@bull.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-04xfrm: Have af-specific init_tempsel() initialize family field of temporary ↵Andreas Steffen
selector While adding MIGRATE support to strongSwan, Andreas Steffen noticed that the selectors provided in XFRM_MSG_ACQUIRE have their family field uninitialized (those in MIGRATE do have their family set). Looking at the code, this is because the af-specific init_tempsel() (called via afinfo->init_tempsel() in xfrm_init_tempsel()) do not set the value. Reported-by: Andreas Steffen <andreas.steffen@strongswan.org> Acked-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Arnaud Ebalard <arno@natisbad.org>
2008-11-03net: '&' reduxAlexey Dobriyan
I want to compile out proc_* and sysctl_* handlers totally and stub them to NULL depending on config options, however usage of & will prevent this, since taking adress of NULL pointer will break compilation. So, drop & in front of every ->proc_handler and every ->strategy handler, it was never needed in fact. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-02udp: Fix the SNMP counter of UDP_MIB_INERRORSWei Yongjun
UDP packets received in udpv6_recvmsg() are not only IPv6 UDP packets, but also have IPv4 UDP packets, so when do the counter of UDP_MIB_INERRORS in udpv6_recvmsg(), we should check whether the packet is a IPv6 UDP packet or a IPv4 UDP packet. Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-02udp: Fix the SNMP counter of UDP_MIB_INDATAGRAMSWei Yongjun
If UDP echo is sent to xinetd/echo-dgram, the UDP reply will be received at the sender. But the SNMP counter of UDP_MIB_INDATAGRAMS will be not increased, UDP6_MIB_INDATAGRAMS will be increased instead. Endpoint A Endpoint B UDP Echo request -----------> (IPv4, Dst port=7) <---------- UDP Echo Reply (IPv4, Src port=7) This bug is come from this patch cb75994ec311b2cd50e5205efdcc0696abd6675d. It do counter UDP[6]_MIB_INDATAGRAMS until udp[v6]_recvmsg. Because xinetd used IPv6 socket to receive UDP messages, thus, when received UDP packet, the UDP6_MIB_INDATAGRAMS will be increased in function udpv6_recvmsg() even if the packet is a IPv4 UDP packet. This patch fixed the problem. Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-01udp: multicast packets need to check namespaceEric Dumazet
Current UDP multicast delivery is not namespace aware. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Acked-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-01xfrm6: handling fragmentNicolas Dichtel
RFC4301 Section 7.1 says: "7.1. Tunnel Mode SAs that Carry Initial and Non-Initial Fragments All implementations MUST support tunnel mode SAs that are configured to pass traffic without regard to port field (or ICMP type/code or Mobility Header type) values. If the SA will carry traffic for specified protocols, the selector set for the SA MUST specify the port fields (or ICMP type/code or Mobility Header type) as ANY. An SA defined in this fashion will carry all traffic including initial and non-initial fragments for the indicated Local/Remote addresses and specified Next Layer protocol(s)." But for IPv6, fragment is treated as a protocol. This change catches protocol transported in fragmented packet. In IPv4, there is no problem. Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-10-31net: replace NIPQUAD() in net/ipv4/ net/ipv6/Harvey Harrison
Using NIPQUAD() with NIPQUAD_FMT, %d.%d.%d.%d or %u.%u.%u.%u can be replaced with %pI4 Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-10-29net: replace %p6 with %pI6Harvey Harrison
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-10-29net: replace %#p6 format specifier with %pi6Harvey Harrison
gcc warns when using the # modifier with the %p format specifier, so we can't use this to omit the colons when needed, introduces %pi6 instead. Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-10-29udp: introduce sk_for_each_rcu_safenext()Eric Dumazet
Corey Minyard found a race added in commit 271b72c7fa82c2c7a795bc16896149933110672d (udp: RCU handling for Unicast packets.) "If the socket is moved from one list to another list in-between the time the hash is calculated and the next field is accessed, and the socket has moved to the end of the new list, the traversal will not complete properly on the list it should have, since the socket will be on the end of the new list and there's not a way to tell it's on a new list and restart the list traversal. I think that this can be solved by pre-fetching the "next" field (with proper barriers) before checking the hash." This patch corrects this problem, introducing a new sk_for_each_rcu_safenext() macro. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-10-29udp: RCU handling for Unicast packets.Eric Dumazet
Goals are : 1) Optimizing handling of incoming Unicast UDP frames, so that no memory writes should happen in the fast path. Note: Multicasts and broadcasts still will need to take a lock, because doing a full lockless lookup in this case is difficult. 2) No expensive operations in the socket bind/unhash phases : - No expensive synchronize_rcu() calls. - No added rcu_head in socket structure, increasing memory needs, but more important, forcing us to use call_rcu() calls, that have the bad property of making sockets structure cold. (rcu grace period between socket freeing and its potential reuse make this socket being cold in CPU cache). David did a previous patch using call_rcu() and noticed a 20% impact on TCP connection rates. Quoting Cristopher Lameter : "Right. That results in cacheline cooldown. You'd want to recycle the object as they are cache hot on a per cpu basis. That is screwed up by the delayed regular rcu processing. We have seen multiple regressions due to cacheline cooldown. The only choice in cacheline hot sensitive areas is to deal with the complexity that comes with SLAB_DESTROY_BY_RCU or give up on RCU." - Because udp sockets are allocated from dedicated kmem_cache, use of SLAB_DESTROY_BY_RCU can help here. Theory of operation : --------------------- As the lookup is lockfree (using rcu_read_lock()/rcu_read_unlock()), special attention must be taken by readers and writers. Use of SLAB_DESTROY_BY_RCU is tricky too, because a socket can be freed, reused, inserted in a different chain or in worst case in the same chain while readers could do lookups in the same time. In order to avoid loops, a reader must check each socket found in a chain really belongs to the chain the reader was traversing. If it finds a mismatch, lookup must start again at the begining. This *restart* loop is the reason we had to use rdlock for the multicast case, because we dont want to send same message several times to the same socket. We use RCU only for fast path. Thus, /proc/net/udp still takes spinlocks. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>